<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>圆</title>
</head>
<body>


半径：<input type="text" placeholder="圆半径" id="a">
周长：<input type="text" placeholder="圆周长" id="b">
面积：<input type="text" placeholder="圆面积" id="c">



<script src="js/script1.js"></script>
</body>
</html>